Poppy tears, opium, heroin, fentanyl: humankind has been in thrall to the "Milk of Paradise" for millennia. A commodity without rival, it is renewable, easy to extract, transport, and refine, and subject to an insatiable global demand. Taking a journey from ancient Mesopotamia to modern America and Afghanistan, Lucy Inglis traces how opiates have influenced medicine, literature, warfare, finance, and law enforcement.